1. Field of the Invention
The present invention relates to devices and methods for capturing and transmitting wireless information and more particularly relates to devices and methods for scanning barcodes on electronic displays and back end systems for utilizing such scanning as in an electronic couponing system.
2. Description of the Background
Symbolic or other graphics-based representations of information are used in many applications to increase the rate at which information can be sent to and received from multiple entities or devices. For example, barcodes, typically found on products or promotions, encode machine-identifiable digital information on printed matter. An exemplary barcode 100 shown in FIG. 1 includes a series of thick 102 and thin 104 vertical bars spaced in an ordered fashion which represent binary or otherwise encoded information. The decimal equivalent 106 of the embedded information is typically printed below the barcode 100.
A conventional barcode includes information at one or both ends indicating which direction the barcode is oriented (in case it is scanned upside-down), and there may be size or scale information embedded in the barcode. There is also a data section that includes the information encoded in the barcode. Typically, barcodes can be of various sizes and may be scanned at different lengths from the scanner. There may be guidelines that determine various characteristics of the barcodes. Preferably, the barcode scanning system of the present invention may be used with conventional barcodes or with a proprietary data encoding mechanism other than the conventional barcode.
Laser-based scanners or other data recognition and acquisition machines are capable of scanning these printed barcodes to identify and decode the encoded information. The information collected by these scanning machines may be used to tally grocery bills, recognize coupons, and classify books or CDs. Barcode scanners and other data recognition and acquisition devices are prevalent because they save time and are convenient to use.
Barcodes may also be displayed on various media other than printed materials. For example, a dynamic barcode may be electronically displayed on a conventional display, such as a CRT (cathode ray tube) or LCD (liquid crystal display). Scannable barcodes may also exist using any other technology capable of producing machine recognizable barcode line orientations.
Although barcodes may be displayed by a variety of different technologies, the simplified “point and scan” technology does not work with all display technologies. For example, because of the light polarization characteristics of an LCD and the laser light used to scan a barcode displayed on the LCD, merely pointing a barcode scanning laser at an LCD will often not result in a successful capture of information. Specifically, lasers can only scan LCD barcodes in polarization angles which allow light to penetrate the LCD.
Laser barcode scanners use a variety of different laser technologies, some of which are prone to changes in the light polarization angle over time. Further, the manufacturers of different display devices, such as cellular telephone LCDs, often use displays with different light polarization angles for different products. It is therefore not possible to guarantee scannability of LCD barcodes without addressing this problem.
It has been previously suggested in other technical fields to apply a quarter wave retarder to the outside surface of an LCD in order to enable the viewing of the LCD through linearly polarized sunglasses. For example, vehicular applications may include instrument panels comprising LCD displays. The light that comes off of these LCDs is linearly polarized (as described below). Therefore, when viewing the light emitted from these LCDs through linearly polarized sunglasses, the brightness of the LCD screen will vary from 100% of the emitted light down to no light depending on the angle between the polarization angles of the LCD and the sunglasses. These very simple applications using a quarter wave retarder to reduce glare coming off of an LCD do not address the somewhat more complicated two-way laser light propagation (both into and out of the LCD display) envisioned by the present invention.
These “scannable” barcodes can be used as part of a larger information system. For example, traditional printed coupons from a manufacturer or other coupon provider are scanned at a cash register to realize an immediate discount on a purchased product (coupon “redemption”). Thereafter, the coupon can be “cleared” between the store and the manufacturer to reimburse the store for this discount. Because the barcode scanning system used in conventional couponing applications is just one form of wireless information transfer, this conventional system may be extended to a plurality of backend information systems.
A need has therefore been recognized in the art to provide a more general solution to the problem of transmitting information from a variety of display devices to a variety of data recognition and acquisition devices. The solution preferably facilitates the scanning of barcodes using conventional laser scanners and LCDs, as well as a variety of other display and scanning technologies. There is also a need to provide new and different backend solutions for utilizing these data acquisition devices, such as in the electronic couponing industry.